refactor(App, navigation): migrate to Expo Router and clean up navigation structure

- Updated App entry point to utilize Expo Router, simplifying the navigation setup.
- Removed legacy navigation components and services to streamline the codebase.
- Adjusted package.json to reflect the new entry point and updated dependencies for compatibility.
- Enhanced overall application structure by consolidating navigation logic and improving maintainability.

src/navigation/paramUtils.ts

@@ -0,0 +1,11 @@
+/**
+ * Expo Router 的 searchParams、动态段可能是 string | string[]
+ * 群 ID 等在应用内一律为 string；路由参数禁止 Number() 以免精度丢失
+ */
+export function firstRouteParam(value: string | string[] | undefined): string | undefined {
+  if (value == null) return undefined;
+  const raw = Array.isArray(value) ? value[0] : value;
+  if (raw == null) return undefined;
+  const s = String(raw).trim();
+  return s === '' ? undefined : s;
+}